* {
    margin: 0;
    padding: 0;
    font-size: 14px;
}
html, body {
    height: 100%;
    width: 100%;
}
#alert {
    z-index:2;
    height: 60%;
    width: 80%;
    position: absolute;
    top: 20%;
    left: 10%;
    overflow: hidden;
    background: #fff;
    border-radius: 4px;
    z-index: 1000;
    display: none;
    padding: 0.5rem;
}
#alert h4 span#close {
    float: right;
    margin-right: 0.6rem;
    font-weight: 500;
    cursor: pointer;
    display: block;
    width: 3rem;
    height: 1rem;
    text-align: center;
    padding: 0.26rem 0.52rem 0.7rem 0.5rem;
    background: #f9f9f9;
    color: #7b7b7b;
    border-radius: 0.5rem;
}
#alert p {
    margin-top: 1.5rem;
    text-align: center;
}
#mask{
    position:absolute;
    top:0;
    left:0;
    height:100%;
    width:100%;
    background:#000;
    opacity:0.3;
    display:none;
    z-index:1;
}